Benefits of Ultrasol®ine K Plus in fertigation in citrus

Iodine is beneficial for root growth and resilience to stress in sweet orange.

Two trials with sweet orange trees in Florida showed that iodine is stored by the trees in the roots, and increases in the leaves. This results in greater root width, with more lateral roots, in a trials on young trees in pots. In an orchard suffering from a variety of sources of stress, it helped to build resilience in trees, to maintain a constant yield of fruits and solids.

A better protection against stress-related yield loss in a sweet orange orchard.

The effect of Ultrasol^®ine was studied in a two-year trial with 12 single tree-replicates in randomised design, orchard with OLL-4 Valencia-type oranges on Cleopatra mandarin rootstock. The trial started when the trees were 4 years after planting. This orchard suffered from multiple stresses. Ultrasol^®ine K Plus was included in the fertilizer programme, at 468 kg/ha/year, applied by drench in 12 split applications. The control treatment consisted of potassium nitrate applied in the same amounts and timing.

In the first year, 5% more fruit developed on the trees with Ultrasol^®ine K Plus compared to potassium nitrate without iodine. In the second year of the trial, the fruit yield in the control was lower than the previous year when iodine was not applied but remained stable when Ultrasol^®ine K Plus was included in the fertilizer programme. This resulted in a statistically significant 40% more fruit compared to the control (LSD, p=0.1). This is a combined effect of the role of iodine in photosynthesis, root functionality and the plant’s anti-stress metabolism.

Iodine levels in the leaves were improved and a better root growth was observed in propagation of Valencia oranges on sour orange rootstock in Florida.

[1] Kirkby, E.A. (2023). Introduction, definition, and classification of nutrients. https://doi.org/10.1016/B978-0-12-819773-8.00016-2